java - Spring 4 + Hibernate 4 配置

Question

我正在尝试进行 Spring 4 + Hibernate 4 配置。但是我在 Controller 中面对 sessionFactory = null 。下面是配置和代码。这个配置有什么错误？

Spring 数据库.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd 
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

    <!-- MySQL data source -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/personal" />
        <property name="username" value="root" />
        <property name="password" value="password" />
    </bean>

    <!-- Hibernate session factory -->
    <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="mappingResources">
            <list>
                <value>/orm/Song.hbm.xml</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
            </props>
        </property>
    </bean>

    <bean id="songDao" class="com.letsdo.impl.SongImpl">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>

    <!-- MUST have transaction manager, using aop and aspects  -->
     <tx:annotation-driven/>
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>
</beans> 

orm/宋/hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="com.letsdo.model.Song" table="song" catalog="personal">
        <id name="id" type="int">
            <column name="id" length="45" />
            <generator class="increment"/>
        </id>
        <property name="filePath" column="filepath"/>
        <property name="fileName" column="filename"/>
        <property name="album" column="album"/>
        <property name="title" column="title"/>
        <property name="size" column="size"/>
    </class>
</hibernate-mapping>

松道.java

public interface SongDao {

    public List<String> getAllAlbums();
}

SongImpl.java

@Service
@Transactional
public class SongImpl implements SongDao{

    private SessionFactory sessionFactory;

    @SuppressWarnings("unchecked")
    public List<String> getAllAlbums(){
        List<String> allAlbums = new ArrayList<String>();
        Query query = getSessionFactory().getCurrentSession().createQuery("Select DISTINCT Album from song");
        allAlbums = query.list();
        return allAlbums;

    }
    public SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }

}

Controller :HomeController.java

public class HomeController {

    @Autowired private SongImpl songDao;
    @RequestMapping(value="/", method=RequestMethod.GET)
    public ModelAndView welcomePageBeforeLogin(HttpServletRequest request, HttpServletResponse response,HttpSession session){
        ModelAndView model = new ModelAndView();
        List<String> album = songDao.getAllAlbums();
        model.addObject("albumsize",album.size());
        model.setViewName("hello");
        return model;
    }
}

Answer 1

我想你最终会得到两个 SongImpl 类的 bean——一个在 xml 中定义(名为 songDao)，另一个用 @Service 注释(默认命名为 songImpl)。后者没有 Autowiring 的 SessionFactory，这就是它为 null 的原因。

您可以在其中一个答案中找到更多信息 here .

If component scanning is enabled, spring will try to create a bean even though a bean of that class has already been defined in the spring config xml. However if the bean defined in the spring config file and the auto-discovered bean have the same name, spring will not create a new bean while it does component scanning.

解决方案是删除 bean 的 xml 版本(如果您不需要它)，并在 SongImpl 中 Autowiring SessionFactory。